1. Field of the Invention
The present invention relates to a tape cassette, and more particularly is directed to a tape having a cassette case with a portion thereof indicating information concerning the type of the tape cassette.
2. Description of the Prior Art
In a known tape player capable of accepting two kinds of tape cassettes for recording two different kinds of signals in accordance with respective signal transmitting systems, problems may arise. One problem is that an information reading member provided in the tape player for reading information indicated on one type of the tape cassettes may hinder a loading operation of the other type of tape cassette into the tape player or may malfunction due to the loading of the other type of tape cassette.
The above problem will be further explained with reference to a tape player capable of accepting both a tape cassette for recording a signal of the NTSC system and a tape cassette for recording a signal of the high definition television (HD) system (the latter will be hereinafter referred to as "HD tape cassette").
At the present time, a tape cassette for recording a signal of the NTSC system may be a VHS tape cassette, a beta tape cassette, an 8-mm tape cassette, or a VHS C tape cassette. In the following discussion only the VHS tape cassette will be considered. However, the problem is not so limited and may apply to any of the tape cassettes for recording a NTSC signal.
As shown in FIGS. 10-12, a VHS tape cassette 1 includes a cassette case 2 which, as a means for indicating predetermined information relating to the tape cassette 1, may have predetermined position at which a hole is, or is not present.
The cassette case 2 of the known tape cassette 1 contains various members including tape reels and, as a result, little free room exists within the cassette case. Therefore, the above-mentioned information indicating hole cannot be formed at a position at which the tape reels or other members are located within the cassette case 2. In other words, the position at which the hole may be formed is limited.
As shown in FIG. 12, two rear corner portions 4 of a lower surface of the cassette case 2 are regions which do not correspond with the various members contained within the cassette case.
Similarly, two rear corner portions of a lower surface of a cassette case of an HD tape cassette, which is similar in external form to the VHS tape cassette 1, are defined as information indicating portions. These indicating portions are shown, for convenience, in FIG. 12 as a plurality of two-dot chain line circles 3 formed at locations on the lower surface of the cassette case 2 of the VHS tape cassette 1 corresponding to the locations that such indicating portions would occupy on the case of an HD tape cassette. In this case, when the VHS tape cassette 1 is loaded into a cassette holder of the tape player, all detection switches for detecting the presence or absence of the holes of the HD tape cassette are undesirably depressed by the lower surface of the cassette case 2.
Further, the two corner portions 4 of the VHS tape cassette 1 are not specified as special areas according to the EIAJ Standard, and thus these portions 4 are normally formed with knurls or surface projections 5, as shown in FIG. 11, for preventing slippage. Accordingly, an upper end of a pin 7 of a detection switch 6 provided in the tape player may abut against a slant surface 5a of the projection 5 as shown in FIG. 13 or, instead, may engage between the adjacent projections 5, thereby possibly causing the detection switch 6 not to operate precisely or to break in response to repeated operations over the long-term. In an attempt to solve this problem, a pin 7' having a sufficiently large upper end may be provided, as shown in FIG. 14. However, in this situation, as is to be appreciated, it is necessary to enlarge the intervals between the detection switches 6, which may result in other problems, for example, it may not be possible to indicate a relatively large quantity of information in a limited region.
Further, in the case of using a non-contact type information reading member, such as a reflection type photosensor, rather than the contact type detection switch 6 mentioned above, a stable reflected light quantity cannot be obtained due to the surface projections 5 of the VHS tape cassette 1, so that malfunctions or misreading of the indicated information may result.